1. Field of the Invention
This invention relates to a moving coil type linear motor.
2. Background of the Invention
Conventionally, there is known a moving coil type linear motor as shown in FIGS. 1 and 2.
In FIGS. 1 and 2, reference numerals 1 and 2 respectively designate magnets each magnetized in the thickness direction thereof and which are fixed to the insides of the yokes 3 and 4 which have their both ends bent such that the same polarity faces each other. Yokes 5 and 6 both penetrate a bobbin 8 on which a moving coil 7 is wound and yokes 5 and 6 are integrated with the yokes 3 and 4 to form a Fig. 8 shape extended in the lateral direction. Reference numeral 11 designates a slide base plate, and on its bottom face there is fixed the coil 7 through a supporting member 9. The slide base plate 11 is provided with slide bearings 12 and 13 on the both sides thereof with which guiding shafts 14 and 15 are engaged.
In the above-mentioned construction, energization of the coil 7 leads to an intersection of a current flowing in the coil 7 and the flux of the magnets 1 and 2 to thereby generate a thrust which moves the coil 7 and consequently the slide base plate 11 in the direction a or the direction b. Such linear motor is employed as, for example, an optical pickup moving device or the like of an optical disc player.
In the above-mentioned conventional linear motor, since the coil 7 for generating the thrust is supported by the guiding shafts 14 and 15 through the slide base plate 11, the whole size and weight of the moving section are large and accordingly the thrust/weight ratio is small, thereby making it impossible to produce a high acceleration. Further, a low mechanical resonance frequency of the moving system causes the frequency bandwidth of the servo system to be narrow.
For this reason, the conventional linear motor has a problem that stable operation at high speed is difficult.